Source

File: wp-includes/general-template.php

function post_type_archive_title( $prefix = '', $display = true ) {
	if ( ! is_post_type_archive() ) {
		return;
	}

	$post_type = get_query_var( 'post_type' );
	if ( is_array( $post_type ) ) {
		$post_type = reset( $post_type );
	}

	$post_type_obj = get_post_type_object( $post_type );

	/**
	 * Filters the post type archive title.
	 *
	 * @since 3.1.0
	 *
	 * @param string $post_type_name Post type 'name' label.
	 * @param string $post_type      Post type.
	 */
	$title = apply_filters( 'post_type_archive_title', $post_type_obj->labels->name, $post_type );

	if ( $display ) {
		echo $prefix . $title;
	} else {
		return $prefix . $title;
	}
}